Portable radiation mapper

In January this year I've come up with idea to combine a radiation detector with GPS. Data collected by such a device would allow me to make a map correlating received radiation dose with geographic location.

Such a map would be very interesting. It's a common knowledge (I hope) that there are many natural radiation sources around, and their density surely varies. Cosmic radiation intensity increases with height above sea level (thinner atmosphere layer to absorb it), ground radiation is not the same everywhere. Also higher radiation is expected where there's more "stuff from underground" exposed - mining areas or rocky terrains. Buildings are build from materials dug from earth, so cities might be more radioactive than, say, forests.

It was my first time working with electronics on my own so I decided to make it as simple as possible. It turns out that parts are commonly available. This is what I got:

• Royaltek RGM-3550 GPS scavanged from an old blutooth gps module
• Arduino Uno
• Seeedstudio SD Card Shield
• Libelium radiation sensor shield
• Chineese power bank with solar panel

This is how these parts look combined:

I am really pleased to see how community centered around Arduino-like projects tries to make electronics as accessible as possible. Plus there are tons of shops with "hacker hardware" designed exclusively to be used in this kind of projects. It's kind of amazing how easy is to build an electronic device such as this one.

I wanted enclosure to be transparent, so I ordered a laser-cut acrylic panels. To combine everything I used a plastic that can be formed with your hands after being heated to 60°C.

 

It was very hard to make it look good since the plastic hardened rather quickly. But then I used a heat gun to soften it wherever I needed and formed it nicely.

Data analysis is done by fairly simple python script. Most crucial parts I've already described: downloading maps and scaling hexes in matplotlib's hexbin function. Scaling is used to visualize statistical uncertainties - small hexes represent points with relatively large uncertainty.

The device has been taking data for two months now with help of my colleagues from scientific club. These are maps: city scale (Kraków, Poland) and country scale (Poland).

It's too soon to draw any conclusions from this data, but new data is being collected even right now.